CN105032917B - Chromium slag leachate contamination soil emergence treating method - Google Patents

Abstract

The invention discloses a kind of chromium slag leachate contamination soil emergence treating method, methods described step is as follows：Step one, the initial concentration scope for determining total chromium in soil surface chromium slag percolate first, when total chrome content is too high in pending chromium slag percolate, water-reducible method beforehand dilution should be taken to process the chromium slag percolate of soil surface, concentration is controlled in the range of 0.157~52.3mg/L；Step 2, by flyash CaO dry-mixed dose be added in the chromium slag percolate of step one, control solid-to-liquid ratio be 2.5~7：50；Step 3, chromium slag percolate and flyash calcium oxide are sufficiently mixed by 7~24h with the mixing speed of 100~300r/min.The present invention it is simple to operate, cheap, pollute it is small, without power consumption, alleviate chromium mud subsequent treatment burden, be that the recycling of flyash lays the foundation.

Description

Chromium slag leachate contamination soil emergence treating method

Technical field

The invention belongs to Environmental Science and Engineering technical field, it is related to a kind of chromium slag leachate contamination soil emergency disposal side Method.

Background technology

Chromium slag belongs to the solid waste discharged during production chromic salts or crome metal, wherein containing with " three cause " effect Cr (VI), therefore be generally acknowledged dangerous solid waste.At present, China's major part chromium slag uses air storage, seepage control measure Imperfection, in Precipitation Process, due to rainwash, water-soluble state and sour solvent Cr (VI) are likely to be permeated the ground by soil, Or pan is formed in floor surface, soil, surface water and underground water to peripheral region are polluted, and have a strong impact on the mankind And other biological health.Therefore, people master should be turned into storing up the reparation of place polluted soil, preventing chromium slag percolate from spreading The target to be paid close attention to.

First, the pollution of chromium recovery technique in soil

The form of the chromium in soil has Cr (III) and Cr (VI), and trivalent chromium exists with slightly solubility hydroxide form, dissociates Trivalent chromium it is few, Cr VI exists in the form of chromate, dissolving, animal migration, strong toxicity.Controlled for the soil by pollution of chromium One of reason approach is to change existence form of the chromium in soil, the thinking of this method be using reducing agent or biology by Cr VI also It is former into trivalent chromium, or auxiliary doses adhesive, reduce the transfer ability of Cr VI；Another approach is from dirty by chromium Removed in the soil of dye, this method is applied to the big soil of infiltration coefficient, by the use of clear water or certain complexing agent as cleaning fluid, by soil Chromium in earth is cleared out, and chromium water is processed again then, and cleaning agent toxicity in itself, biodegradability limit this The development of technology, in addition to the after-treatment containing chromium water also for the operation of the method increases cost.

2nd, chromium slag percolate disposal technology

Chromium in percolate exists in the form of trivalent chromium and Cr VI, and both forms can be converted mutually, so, for total The treatment of chromium has more realistic meaning.At present, the processing method report on chromium slag percolate is a lot of both at home and abroad, mainly has：1、 The precipitation method：By chromate waste water and the barium salt reaction insoluble chromic acid precipitated barium of generation, this method is applied to containing Cr VI waste water high, excellent Point is high treating effect, and processing cost is low, easy to operate, has the disadvantage that barium salt consumption is big, more difficult, the sludge quantity of generation of originating Greatly, complex treatment process physical-chemical process；2nd, biological treatment：The main function bacterium using domestication is inhaled to the electrostatic of chromate waste water Chromium in attached effect, the catalyzed conversion effect of enzyme, complexing, flocculation, co-precipitation removing waste water, this method operation side Just, operating cost is relatively low, but the biological sludge for producing easily causes secondary pollution；3rd, absorption method：Using sorbing material or modified Sorbing material chromium in waste water is removed to the suction-operated of chromium, the shortcoming of this method is low regeneration efficiency, and service life is short, treatment It is costly；4th, electrochemical process：Cr (VI) is reduced into the less Cr of toxicity (III) using cell reaction, by the residue for producing Cr VI in treatment waste water, its advantage is simple to operate, takes up an area less, has the disadvantage that power consumption is big, and effluent quality is poor, and is produced a large amount of Reluctant sludge；5th, chemical reduction method：It is in acid condition that toxicity is higher by reducing agent is added in chromate waste water Cr (VI) be reduced into the less Cr of toxicity (III), then using NaOH or lime regulation pH, make Cr (III) with hydroxide The form of precipitation separates removal from water body.These methods have a respective excellent, shortcoming, but no matter which kind of method, can all produce and contain Chromium solid waste, if do not carried out resource recycling, will be related to the secondary pollution of chromium mud, or to being enriched with the biology of chromium Subsequent treatment problem.

3rd, modified coal ash is to wastewater processing technology

China is mainly to the minimizing technology of chromium-bearing sludge simply banks up or fills, the fixation-stabilization processes of chromium, resource Change is processed, with potential research and application value.Fixation-the stabilization processes of chromium mainly have cement-based solidified skill in sludge Art, lime curing technology, plastic material encapsulation techniques, large-scale encapsulation techniques, from knot curing technology, glass solidification method.

Flyash is a kind of mixing material like volcano grey matter that coal dust is formed after high-temp combustion, by multi mineral composition Composition, the hydraulic cementing materials that can be made into levigate with Portland clinker and proper amount of gypsum can play the stabilization of chromium, consolidate It is set for using, porous loose structure, as sorbent treatment chromate waste water, serves the effect for turning waste into wealth, has extensively Application and economic worth.Flyash by physical absorption, chemisorbed, ion exchange absorption, Electrostatic Absorption, flocculation adsorption, Pollutant in the effect removal waste water such as precipitation and filtering.Although flyash is with larger specific surface area, individually as suction Attached dose for the treatment of waste water, effect is unsatisfactory, but by after modified active treatment, adsorption capacity is greatly improved, should as adsorbent For serving the effect for turning waste into wealth in wastewater treatment, it is widely used and economic worth, realizes the sustainable profit of resource With.At present, mainly have that modification by fire, acid system are modified, alkaline process is modified, PDMDAAC is modified for modified coal ash method of modifying and Being modified for other methods, is widely used in treatment heavy metal wastewater thereby, waste water from dyestuff, oils phenol waste water, phosphorus-containing wastewater and reason and contains Fluorine is useless etc..Cu in vertical contention modification by fire flyash post processing water²⁺, pH 7.0, when mixing time is 10min, Cu²⁺Go Except rate is 87.6%；Cao Xianyan etc. post-processes waste water from dyestuff with PDMDAAC modified coal ash, when dosage is 20g/L, reaction 80min, percent of decolourization is more than 84%, and the treatment effect of modified coal ash is better than that PDMDAAC is used alone.Wang Jinmei etc. uses oxygen Change calcium modified coal ash waste water of the post processing containing fast scarlet 4 BS dyestuff, research shows to exist in the mass concentration of waste water from dyestuff COD During 356.8mg/L, dosage is 20g/L, pH 10.5 or so, and COD clearances reach 95%, can reach discharging standards.King Processed with 1mol/LCaO modified coal ash for sesame etc. in the simulated wastewater for containing Acid Blue 40 0mg/L, research shows：When modified powder Coal ash dosage is 200g/L, when adsorption time is 40min, pH 6 or so, and clearance is up to 92.64%.Old snow is elementary to fine coal The modified research for preparing phosphorus removing agent of ash, containing phosphorus concentration between 0.5~50mg/L, through acid and the modified fine coal of ferrous salt After ash treatment, water outlet is less than 0.5mg/L, reaches national sewage phosphorus discharge primary standard.Peng Ronghua et al. is using troilite, chlorination After sodium, hydrochloric acid carry out a series of activation process to flyash, research shows to work as Cr⁶⁺Below initial concentration 50mg/L, Cr⁶⁺Removal Rate is more than 96%, but pH influences it to Cr⁶⁺Clearance.Xiao Wen perfume (or spice) et al. utilizes modified cement flyash, when proportioning is 17: 3, Cr⁶⁺Initial concentration is 5mg/L, and pH 4.0, dosage is 1g/L, adsorbs 6h, Cr⁶⁺Clearance be 95%.

At present, domestic scholars are for flyash except the research of chromium is directed to Cr VI mostly, and the research to total chromium is less, and Powder ash adsorption efficiency is improved to generally require to be modified, and modified adsorption effect is limited.

Humus has important work as organic principle main in soil, migration, conversion to heavy metal in soil It is the part for being dissolved in alkali in humus and not dissolving in acid with, wherein HA, very big ratio is occupied in humus, contains in HA molecules There are substantial amounts of phenyl ring, thick phenyl ring and various heterocycles, there is bridged bond to be connected between each ring again, there is carboxyl, phenolic hydroxyl group, quinone on ring and side chain The various functional groups such as base, methoxyl group, sulfonic group, amido, humic acid because negatively charged and cation exchange capacity is high, while having very well Complex performance, can be acted on many heavy metals, influence heavy metal ion form in the environment and migration, and then also influence Absorption behavior of the different adsorbents to metal ion.On the other hand, humic acid is used as the very strong compound of redox active, energy Some metal ions in reducing environment.Therefore, humic acid and Cr (VI) interaction relationship, corruption in total chromium processing procedure are studied Phytic acid is to CaO, the influence of the total chromium of flyash treatment, and the in-situ treatment of chromium slag percolate is also very necessary.Humic acid There are many reports with the repercussion study of Cr VI, because the chemical composition of humic acid is not fixed, redox between the two is anti- The more difficult determination of quantitative relationship answered.

The content of the invention

The purpose of the present invention is that the research of chromium effect is removed by combining to Fly ash-CaO, discusses Fly ash-CaO to total The cutting mechanisms of chromium, by enter row element complete analysis to processed waste water and to treatment after residual residue toxicity characteristic leaching procedure Research, it was demonstrated that Fly ash-CaO joint not only has preferable treatment effect to total chromium, moreover it is possible to effectively in treatment chromium slag percolate Other toxic heavy-metal elements, while the leaching of flyash Poisoning composition is also limited, it thus provides a kind of chromium slag percolate Middle chromium-polluted soil is more quick, the convenient, emergence treating method of of low pollution.

The purpose of the present invention is achieved through the following technical solutions：

A kind of chromium slag leachate contamination soil emergence treating method, comprises the following steps：

Step one, the initial concentration scope for determining total chromium in soil surface chromium slag percolate first, when pending chromium slag When total chrome content is too high in percolate, to reach removal amount higher, water-reducible method beforehand dilution treatment soil should be taken The chromium slag percolate on surface, concentration is controlled in the range of 0.157~52.3mg/L.

Step 2, flyash-calcium oxide intermixture is determined according to the initial concentration and contaminated scope of chromium slag percolate Add total amount, according to the cumulative volume of polluted soil surface chromium slag percolate, by Fly ash-CaO, dry-mixed dose is added to soil In the chromium slag percolate on surface, solid (Fly ash-CaO) liquid (chromium slag percolate) is controlled than being 2.5~7: 50.

In this step, the two mass ratio is 2: 0.5~5 in dry-mixed dose of the flyash-calcium oxide, and optimum quality ratio is 2: 1 or 2: 2.

In this step, the optimal solid-to-liquid ratio is 4: 50.

Step 3, chromium slag percolate and flyash-calcium oxide are sufficiently mixed with the mixing speed of 100~300r/min, Through aquation, fix 7~24h after, the waste water after treatment is extracted, is discharged, remaining solid residue can with Portland clinker, Slag etc. is mixed and made into hydraulic material so as to realize further stabilization-immobilization treatment.

In this step, the optimal mixing speed is 150r/min.

In this step, the optimal aquation, set time are 24h.

The invention has the advantages that：

1st, the present invention leaches water as research object with chromium slag, the condition of chromium pulp water contaminated soil is simulated, with Fly ash-CaO It is inorganic agent, it is studied with total chromium interaction mechanism and influence factor, it is determined that flyash, CaO the optimum mix amount Than demonstrating the reliability of technical method.Research shows：Under the conditions of 25 DEG C of room temperature, the rotating speed of 150r/min fully vibrates 24h, fixed flyash consumption, adds the CaO of different quality, and with the increase of CaO mass, the clearance of total chromium gradually increases, To the waste water of higher concentration, when selection Fly ash-CaO proportioning is 2: 2, the utilization rate highest of CaO, and average every gram of inorganic agent Treating capacity is maximum.Shown by blank, check experiment research, flyash, CaO are used in combination and the removal effect of total chromium is much larger than The treatment effect of flyash or CaO as adsorbent is used alone, its mechanism of action is probably flyash, CaO in hydration reaction During chromium can be fixed in crystal structure.By entering row element complete analysis to processed waste water, research show flyash- CaO is used in combination can not only process total chromium in chromium slag percolate, moreover it is possible to other toxic heavy-metal elements in effective processing solution, together When also to limit leaching of the solid residue after the leaching of flyash Poisoning composition, and treatment to total chromium inhibited.Cause This, this method by the soil of chromium slag leachate contamination, prevents it from being spread to around soil and depths, with important emergency processing Realistic meaning.

2nd, the method is not limited by pH, it is not necessary to the acidity of the former chromium water of regulation, without being modified to flyash, is saved Cr (VI) is reduced into the process of Cr (III), it is to avoid in chromium slag percolate adding reducing agent to soil in reduction precipitation method The defect of the secondary pollution that earth is likely to result in.

3rd, at present, domestic for the soil of sudden chromium slag leachate contamination, the emergency processing for not having feasibility is arranged Apply, can be fixed for the chromium slag percolate of chromium slag percolate chromium slag percolate or upper soll layer by this method, used as in-situ treatment One kind of method, effectively prevents or slows down percolate and spread from topsoil to deep soil, simple to operate, cheap, nothing Pollution.From promoting the well-being of mankind, angle is said, limits the flyash dissolution containing some toxic heavy metals in itself, solves part flyash Random heap is rivals in a contest the problem that soil, surface water, underground water etc. are polluted.

4th, the adsorption capacity of flyash is improved, solution loss amount is small, mitigates the subsequent treatment burden of adsorption saturation ash, is fine coal The recycling of ash lays the first stone,

5th, it is simple to operate, cheap, pollute it is small, without power consumption, alleviate chromium mud subsequent treatment burden, be flyash Recycling lays the foundation.

Brief description of the drawings

Fig. 1 is flow chart；

Fig. 2 is the stripping quantity curve of total chromium in flyash；

Fig. 3 is other element dissolubilities (mg/L) in different time powdered coal ash；

Fig. 4 is the influence that duration of oscillation removes total chromium to flyash；

Fig. 5 is influence of the dosage of flyash to total chromium adsorbance；

Fig. 6 is influence of the duration of oscillation to the total chromium effect of Fly ash-CaO combined removal；

Fig. 7 is equilibrium concentration and treating capacity matched curve；

Fig. 8 is influence of the different time CaO throwings amount to the total chromium of Fly ash-CaO combined removal；

Fig. 9 is the influence that duration of oscillation removes total chromium to CaO；

The influence that CaO dosages are removed to total chromium when Figure 10 is initial concentration 49.11mg/L；

The influence that CaO dosages are removed to total chromium when Figure 11 is initial concentration 22.78mg/L；

The influence that Figure 12 is removed for the modification agent of different time different ratio to total chromium；

Figure 13 is vibration 0.5h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 14 is vibration 1h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 15 is vibration 2h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 16 is vibration 3h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 17 is vibration 5h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 18 is vibration 7h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 19 is vibration 24h wet mixings agent, dry and wet agent to total chromium removal effect comparison diagram；

Figure 20 is flyash surface texture (1000 ×)；

Figure 21 is flyash surface texture (5000 ×)；

Figure 22 is flyash EDX energy spectrum analysis；

Figure 23 is the modified flyash surface texture (1000 ×) of CaO aquations；

Figure 24 is the modified flyash surface texture (5000 ×) of CaO aquations；

Figure 25 is the modified flyash EDX energy spectrum analysis of CaO aquations；

Figure 26 is the surface texture of the residue containing chromium (1000 ×) after Fly ash-CaO Combined Treatment；

Figure 27 is the surface texture of the residue containing chromium (5000 ×) after Fly ash-CaO Combined Treatment；

Figure 28 is the EDX energy spectrum analysis of residue containing chromium after Fly ash-CaO Combined Treatment；

Figure 29 is XRD ray spectrums after former flyash and Fly ash-CaO hydration reaction, (a) original flyash XRD ray light Spectrum, (b-g) CaO aquation modified coal ash：B (flyash: calcium oxide=2: 0.5), c (flyash: calcium oxide=2: 1), d (powder Coal ash: calcium oxide=2: 2), e (flyash: calcium oxide=2: 3), f (flyash: calcium oxide=2: 4), g (flyash: calcium oxide =2: 5), ◆：Ca(OH)₂；★：SiO₂；●：Calcite；

Figure 30 XRD crystal analyses, (a) flyash-C_aWet mixing agent after O (2: 2) hydration reaction, (b) Fly ash-CaO (2 : the 2) residue containing chromium after dry blending process, ◆：Ca(OH)₂；▲：Chromate；★：SiO₂；●：Calcite；

Figure 31 is the wet mixing agent infrared spectrogram after former flyash, Fly ash-CaO aquation；

Figure 32 is dry-mixed for the wet mixing agent after former flyash, Fly ash-CaO (2: 2) hydration reaction, Fly ash-CaO (2: 2) The infrared spectrogram of residue containing chromium after treatment, (a) original flyash, the wet mixing agent after (b) 2: 2 hydration reaction, (c) 2: 2 dry-mixed place Residue containing chromium after reason；

Figure 33 is the fluorescent material fluorescence spectra in water lotion；

Figure 34 is the fluorescent material fluorescence spectra in pickling washing lotion；

Figure 35 is HA fluorescence spectras after purification；

Figure 36 is resulting HA solids IR Characterization after the treatment of each step；

Figure 37 is influences of the pH to humic acid ultravioletvisible absorption intensity；

Figure 38 is that ionic strength is 0.5,0.05 time Cr (VI) ion distribution situation；

Figure 39 is the UV, visible light maximum absorption wavelength change of chromate under different pH；

Figure 40 is humic acid fluorescence intensity rule under different pH；

Figure 41 is humic acid oxidation efficiency change under different pH, difference Cr (VI) concentration；

Figure 42 is HA calibration curve equations；

Figure 43 is Cr (VI) and HA quantitative relationships；

Figure 44 is influences of the HA to the total chromium of Fly ash-CaO combined removal；

Figure 45 be stoste in contain HA, supernatant three-dimensional fluorescence spectrum after Fly ash-CaO (2: 2) dry blending process；

Figure 46 be stoste in contain HA, Fly ash-CaO (2: 5) treatment after supernatant three-dimensional fluorescence spectrum.

Specific embodiment

Technical scheme is further described below in conjunction with the accompanying drawings, but is not limited thereto, it is every to this Inventive technique scheme is modified or equivalent, without deviating from the spirit and scope of technical solution of the present invention, all should be covered In protection scope of the present invention.

The present invention is to process target with chromium slag percolate, there is provided a kind of chromium slag leachate contamination soil emergency disposal side Method, as shown in figure 1, particular content is as follows：

1st, test material and instrument

1.1 flyash

Experiment flyash used takes from Harbin Power Co., Ltd., and XRF elementary analyses, analysis knot are carried out to raw material Fruit is shown in Table 1-1, and main oxidation chemical structure is shown in Table 1-2.

Table 1-1 flyash constituent analyses

Element	O	Na	Mg	Al	Si	S	K	Ca	Cr	Rb	Mn	P
													Content %	31.73	2.221	0.436	7.059	18.30	0.264	0.569	7.95	0.006	0.002	0.122	0.033
Element	Fe	Cu	Zn	As	Sr	Y	Nb	Pb	Bi	Ti	Cd
													Content %	3.67	0.009	0.01	0.005	0.098	0.001	0.001	0.004	0.01	0.453	＜ 0.001

Table 1-2 main oxidation chemical structures

SiO2	Al2O3	CaO	Fe2O3	Na2O	P2O5	K2O	SO3	MgO	TiO2	MnO	Cr2O3
												39.221	13.334	11.126	5.243	2.994	1.392	1.371	0.800	0.727	0.755	0.157	0.009

1.2 chromium slags

Experiment chromium slag used takes from Jinzhou, Liaoning chromic salts chemical plant, and XRF analysis, analysis result such as table 1- are carried out to raw material Shown in 3.

Table 1-3 chromium slag ingredients are analyzed

Element	O	Na	Mg	Al	Si	S	Cl	K	Ca	Cr
											Content %	44.15	3.30	12.54	3.50	3.81	0.19	0.23	0.07	18.93	4.69
Element	Fe	Cu	Zn	Mn	V	Zr	Ti	Ni	Co	Cd
											Content %	7.92	0.01	0.03	0.28	0.046	0.004	0.145	0.10	0.039	＜ 0.001

1.3 chemical reagent

Experiment chemical reagent used, as shown in table 1-4.

Table 1-4 chemical tests grade and producer

Reagent name	Grade	Producer
			Calcium oxide	Analysis is pure	Tianjin Zhi Yuan chemical reagent Co., Ltd
Humic acid	Analysis is pure	Tianjin recovery fine chemistry industry research institute
			Potassium chromate	Top pure grade	Tianjin recovery development in science and technology Co., Ltd
Sulfuric acid	Analysis is pure	Tianjin Chemical Reagents Factory No.1
			Hydrochloric acid	Top pure grade	Tianjin Jin Feng Chemical Co., Ltd.s
NaOH	Top pure grade	Tianjin recovery development in science and technology Co., Ltd
			Hydrofluoric acid	Top pure grade	Guangdong Xilong Chemical Co., Ltd

1.4 test apparatuses

Experiment instrument, as shown in tables 1 to 5.

Table 1-5 test apparatuses model and producer

Instrument title	INSTRUMENT MODEL	Instrument producer
			Inductively coupled plasma atomic emission	5300DV	U.S. PerkinElmer
SEM	QuantA 200	U.S. FEI
			XRF XRFs	AXIOS-PW4400	Dutch PANalytical
XRD	D8ADVNCE	German Bruker
			Cyclotron oscillation device	HY-5	Changzhou Guohua Electric Appliance Co., Ltd.
Magnetic stirring apparatus	79-1	Tianjin Sai get Li Si experimental analysis instrument manufacturings factory
			Desk-top ultrapure water equipment	MILLI-QII types	U.S. MILLIPORE
Ultrasonic washing instrument	KQ-500E	Kunshan Ultrasonic Instruments Co., Ltd.
			Infrared spectrometer	Spectrum One	U.S. PerkinElmer

2nd, content of the test

2.1 analysis methods

2.1.1 total chromium mark feed method

Inductively coupled plasma atomic emission：ICP-AES spectrometer frequency is 40.68MHz；Plasma torch pipe：Three layers Concentric quartz tubes, detachable torch pipe；Radio-frequency signal generator：Peak power output is 1300W, plasma (orifice) gas (cooling gas)：Argon gas Flow velocity：15L·min^-1；Auxiliary gas：Argon gas flow velocity：0.2L·min^-1；Carrier gas (atomization gas)：Argon gas flow velocity 0.8Lmin^-1；See Survey height：At actuating coil above 15mm.

2.1.2 material SEM surface textures are characterized

The type SEM of QuantA 200 (U.S. FEI, attached U.S. EDAX Genesis2000 X-ray power spectrums Instrument)：Resolution ratio：Environment vacuum pattern 3.0nm@30kV；Backscattered electron 4.0nm@30kV；Accelerating potential 200V~30kV；Put Big multiple：1000 ×, 5000 ×.

2.1.3 XRD Crystal Structures

D8 ADVNCE types X-ray diffractometer (German Bruker), test condition：10 °≤2 θ≤90 °, CuK α,Voltage 40kV, electric current 40mA.

2.1.4 structure of functional groups characterizing method

Using KBr pressed disc methods, wave number is 4000cm^-1~400cm^-1, scanning times are 10 times, and instrumental resolution is 4cm^-1。

2.1.5 the assay method of humic acid

Fluorescent spectrometry：The scan mode of analysis method is 3D Scan；The sweep limits of excitation wavelength be 220~ 450nm, it is 5nm to space between, and spectral bandwidth is 5nm；The sweep limits of launch wavelength be 220~600nm, mutually it Between at intervals of 1nm, spectral bandwidth is 5nm；Response time is 0.01ns；PMT voltage is 700V；Sweep speed is 1200nm/ min。

2.1.6Cr (VI) ultraviolet-visible spectral property

Ultraviolet-visible spectrophotometry：1cm colorimetric pools, sweep speed is middling speed, sampling at intervals of 2nm, wavelength is swept Scope is retouched for 200~700nm.

2.2 test methods

2.2.1 flyash blank test

2.2.1.1 the preparation of chromate waste water is simulated

The preparation of chromium slag percolate：20g chromium slags are taken, adds 1L ultra-pure waters, glass bar to mix chromium pulp water after stirring Thing to be placed and stir 1h on magnetic stirring apparatus, and the static supernatant that taken to 24h, after separation of solid and liquid is made high-concentration chromium-containing wastewater, dilute Release stand-by.

2.2.1.2 the water-soluble shaking test of flyash

2.00g, 4.00g, 6.00g flyash are taken, 50mL is added separately to and is gone in ultra-pure water, filled with the rotating speed of 150r/min Divide vibration, be sampled in 0.5h, 1h, 2h, 3h, 5h, 7h, 24h, the concentration of total chromium is examination index, research with solution Total chromium stripping quantity in aqueous in different duration of oscillation powdered coal ash, and examine or check the powdered coal ash during vibration In other toxic elements dissolution situation.

2.00g CaO will be mixed into 2.00g flyash, be added to 50mL and go in ultra-pure water, the rotating speed of 150r/min is abundant Vibration 24h, the concentration of total chromium is examination index with solution, examines or check influence of the addition of CaO to total chromium dissolution in flyash.Together When defects inspecting is carried out to 2g CaO raw materials.

2.2.1.3 the influence of duration of oscillation

6.00g flyash is taken, is added in 50mL chromium slag percolates, under the conditions of 25 DEG C of room temperature, with turning for 150r/min Fast fully vibration.It is sampled in 0.5h, 1h, 2h, 3h, 5h, 7h, 24h respectively, static 4min during per sub-sampling takes supernatant Liquid carries out inductively coupled plasma atomic emission measure, and examination adsorption time removes the influence of total chromium to flyash.

2.2.1.4 the influence of solid-to-liquid ratio

0.50g, 1.00g, 2.00g, 3.00g, 4.00g, 5.00g, 6.00g, 7.00g flyash are taken, is added separately to The total chromium concns of 50mL are the chromium slag percolate of 22mg/L, and sample-adding interval time is 1min, under the conditions of 25 DEG C of room temperature, with 150r/ The rotating speed of min fully vibrates 24h.Taking supernatant carries out inductively coupled plasma atomic emission measure, to examine or check flyash throwing Measure the influence to total chromium removal effect.

2.2.2 the research of the efficiency of the total chromium of Fly ash-CaO combined removal

2.2.2.1 influence of the duration of oscillation to the total chromium effect of Fly ash-CaO combined removal

Flyash and each 2.00g of CaO are taken, after being well mixed, 50mL total chrome content 22.78mg/L chromium slag percolates is added to In, under the conditions of 25 DEG C of room temperature, fully vibrated with the rotating speed of 150r/min, respectively 0.5h, 1h, 2h, 3h, 5h, 7h, It is sampled during 24h, examines or check the effect of the total chromium of Fly ash-CaO combined removal under different duration of oscillations.

2.2.2.2 influence of the concentration of total chromium to the total chromium effect of Fly ash-CaO combined removal

The mixture several pieces of flyash and each 2.00g of CaO are taken, the chromium of 0.1~190mg/L concentration ranges is added separately to In slag percolate, under conditions of 25 DEG C of room temperature, 24h is fully vibrated with the rotating speed of 150r/min, with the balance of total chromium in solution Concentration is abscissa, and the total chromium milligram number handled by every gram of mixture is ordinate, is carried out curve fitting.

2.2.2.3 the dosage of CaO removes the research of total chromium efficiency to flyash

Replace the flyash of part with CaO, i.e., by the way of CaO is mixed into flyash, take six parts of flyash 2.00g, Put into after being well mixed with 0.50,1.00,2.00,3.00,4.00,5.00g CaO respectively known to 50mL each element contents In chromium slag percolate, under conditions of 25 DEG C of room temperature, fully vibrated with the rotating speed of 150r/min, sample time be 0.5,1,2,3, 5th, 7,24h, examination both combine removal effect to total chromium.And to being processed through 24h after chromium slag percolate enter row element and divide entirely Analysis, the synergy that examination Fly ash-CaO synergy is removed to other elements.

2.2.2.4 total chromium leaching test of residue after processing

Selection flyash, CaO, three kinds of inorganic agents of form of Fly ash-CaO, solid-to-liquid ratio are respectively 4: 50,5: 50,6: 50, 7: 50, chromium slag percolate is processed.Operating condition is：Under the conditions of 25 DEG C of room temperature, filled with the rotating speed of 150r/min Static to 24h after dividing vibration 7h, after separation of solid and liquid, supernatant determines total chromium concn, and solid residue adds 50mL ultra-pure waters, fully After mixing, static 24h examines or check the leaching content of total chromium, and testing program is as shown in table 2-1.

The table 2-1 testing program tables of comparisons

2.2.3 the check experiment that CaO is removed to total chromium

2.2.3.1 the influence of duration of oscillation

CaO is added in 50mL total chrome contents respectively 49.11mg/L chromium slag percolate in the way of solid-to-liquid ratio 4: 50, Under conditions of 25 DEG C of room temperature, fully vibrated with the rotating speed of 150r/min, different time sampling, the examination time is total to CaO removals The influence of chromium.And be compared with the effect of the total chromium of Fly ash-CaO Combined Treatment.

2.2.3.2 the influence of CaO dosages and the initial concentration of total chromium

Be 49.11mg/L to six parts of total chromium concns respectively, the 50mL chromium slag percolates that six parts of total chromium concns are 22.78mg/L In add 2.50g, 3.00g, 4.00g, 5.00g, 6.00g, 7.00g CaO, under conditions of 25 DEG C of room temperature, with 150r/min's Rotating speed fully vibrates 24h, when individually being added under two kinds of concentration conditions of examination CaO to the removal effect of total chromium, and with exclusive use Flyash, Fly ash-CaO are combined the effect for removing total chromium as inorganic agent and are compared.

2.2.3.3 the influence of the dosing method of CaO

Total chromium in CaO joint flyash removal chromium slag percolates, dosing method one is to take both to be direct plungeed into after mixing To in chromium slag percolate, mode two is that aquation after both are mixed plus a small amount of is prepared into inorganic agent, it is hardened after, with powder Form put into chromium slag percolate.Aquation method to prepare modified coal ash (abbreviation wet mixing agent) method as follows：With flyash It is raw material with CaO, is fully mixed, add appropriate water, mixture is formed walk shape but without under current, hardens at room temperature anti- Answer finely ground, the sieve of 50 mesh of mistake after 24h.Its proportioning is respectively A (16.80g flyash+4.20g CaO), B (14.00g flyash + 7.00g CaO), C (10.50g flyash+10.50g CaO), D (8.40g flyash+12.60g CaO), E (7.00g fine coal Ash+4.00g CaO), F (6.00g flyash+15.00g CaO).

To six kinds of wet mixing agent A 2.50g, B 3.00g, C 4.00g, D 5.00g, E are put into chromium slag percolate respectively 6.00g, F 7.00g, six parts of dry-mixed dose of A ' (2.00g flyash+0.50g CaO), B ' (2.00g flyash+1.00g CaO), C ' (2.00g flyash+2.00g CaO), D ' (2.00g flyash+3.00g CaO), E ' (2.00g flyash+4.00g CaO), F ' (2.00g flyash+5.00g CaO), under conditions of 25 DEG C of room temperature, is fully vibrated with the rotating speed of 150r/min, different Sampled under time conditions, the wet mixing agent of identical solid-to-liquid ratio and wet mixing agent are compared, the feed postition for examining or check CaO goes to total chromium Except the influence of rate.

2.2.4 the research of the total chromium curing mechanism of Fly ash-CaO combined removal

By powdered coal ash, CaO aquations modified coal ash and treatment after residue containing chromium do SEM, XRD, IR Characterization respectively, The total chromium curing mechanism of Fly ash-CaO combined removal is discussed.

For the ease of the research of the material characterization and mechanism of curing mechanism, 4g Fly ash-CaOs (2.00g+2.00g) are put In 50mL 2g/L K₂CrO₄In solution, under conditions of 25 DEG C of room temperature, 24h, solid-liquid point are fully vibrated with the rotating speed of 150r/min Solid residue is dried treatment at room temperature after.

2.2.5 the research of technology restriction factor

2.2.5.1 the purifying of humic acid

Two parts of commercially available humic acid samples of 10g are taken, 50mL ultra-pure waters are separately added into, after carrying out ultrasonically treated 10min, collected In filtrate to 100mL volumetric flasks, water-soluble filtrate 1,2 is obtained after constant volume, insoluble solid is fully transferred on qualitative filter paper, obtained Filter cake 1,2.By the HF mixed liquid dippings of the 0.1mol/LHCl+0.3mol/L of 10mL of filter cake 2,12h is vibrated at room temperature, from Heart treatment, and being washed with HCl+HF repeatedly, to ash content it is minimum after, merging filtrate obtains acid-soluble filtrate 3 in 100mL volumetric flasks, After filter cake washing deacidification, put into 60 DEG C of baking ovens and dry to obtain filter cake 3, i.e., humic acid after purification.Filtrate 1,3 is done into fluorescence spectrum Analysis, filter cake 1,3 does infrared spectrum analysis.

Lower drying, until humic acid quality is not changing after purification, weighs 4g at a temperature of filter cake 3 is placed in into 105 DEG C Powder sample, after being dissolved with the NaOH solution that concentration is 1mol/L, then with the HCl solution regulation pH that concentration is 1mol/L into Property, using ultra-pure water by its constant volume in 1L volumetric flasks, the quality of humic acid in filtrate is calculated by weight method, and prepare It is stand-by into storing solution.Humic acid solution 4 after purification is obtained after storing solution is diluted, and does spectrofluorimetry.

2.2.5.2 pH is to humic acid and the spectral characterization of chromium influence factor

(1) researchs of the pH on the ultravioletvisible absorption characteristic influence of humic acid and chromium

With 1% H₂SO₄Humic acid is configured to two parts of concentration of pH difference 3.0,7.0 for the rotten of 12.5mg/L is planted by solution Acid solution.Meanwhile, prepare 40mg/L K₂CrO₄PH be 1~12 Cr (VI) solution, scope be 200~700nm in carry out UV-Vis scans, examine or check influences of the pH to humic acid and the ultravioletvisible absorption characteristic of chromium respectively.

(2) influences of the pH to humic acid fluorescence spectrum

With 1% H₂SO₄It is the humic acid solution that 1~12, concentration is 12.5mg/L, examination that solution is configured to a series of pH The Changing Pattern of humic acid fluorescence intensity under condition of different pH.

(3) pH reduces the research of Cr (VI) influences on humic acid

It is the humic acid solution of 12.5mg/L to take the concentration under condition of different pH, is separately added into the Cr (VI) of quality, is examined or check PH reduces the influence of Cr (VI) effect to humic acid.

2.2.5.3 the structure of humic acid and original Cr (VI) quantitative relationship

Humic acid and Cr (VI) are a more rapid courses of reaction, and need not be higher temperature, therefore, fixed reaction The pH of solution, adds Cr (VI) solution of various concentrations, at ambient temperature (25 in concentration is for the humic acid of 12.5mg/L DEG C) reaction 10min, as abscissa, the fluorescence intensity of humic acid is ordinate, research humic acid and original Cr to the concentration with Cr (VI) (VI) semidefinite magnitude relation, sets up calibration curve equation.

2.2.5.4 humic acid is to flyash, the influence of the total chromium effect of CaO combined removals

Four parts of total chromium concns are taken for 22.78mg/L chromium slag percolates, by the quantitative relationship result of 2.2.5.3, thereto Certain density humic acid solution is added in two parts, now, humic acid excess, Cr (VI) has been completely converted into Cr (III).By powder Coal ash and CaO are well mixed with 2: 2,2: 5 ratio, are respectively put into four parts of chromium slag percolates.Vibrate at ambient temperature 24h, taking supernatant carries out the analysis of total chrome content.And to being processed through Fly ash-CaO after supernatant (in stoste contain humic acid) Carry out the measure of three-dimensional fluorescence spectrum.

3rd, result and discussion

3.1 flyash blank tests

3.1.1 the element of simulation chromate waste water is constituted

The element composition of table 3-1 simulation chromate waste waters

From table 3-1, the non-dissolution of composition such as element Cu, Zn, Ni, Co, Mn, Ti, V in chromium slag raw material.

3.1.2 the water-soluble shaking test of flyash

From table 3-2, in identical duration of oscillation, the stripping quantity of total chromium is relevant with the quality of flyash in flyash, The quality of flyash is in certain linear relationship with the stripping quantity of total chromium.In 0.5~24h time ranges, average every gram of fine coal Total chromium stripping quantity curve is as shown in Figure 2 in ash.As seen from the figure, with the change of duration of oscillation, the stripping quantity of total chromium gradually rises, Tended to balance in 24h.The stripping quantity curve of other elements is shown in Fig. 3 in powdered coal ash, as seen from the figure, during vibration Element such as S, Na, B in powdered coal ash, Al, water solubility Si have more dissolution, and Fe, As, Ni, Ba, Sb, K, Mg, V, Mo have The non-dissolution of element in the powdered coal ash such as a small amount of dissolution, Cu, Zn, Pb, Cd, Ti, in view of the mistake that powdered coal ash soaks in water The dissolution of part poisonous and harmful substance is had in journey, flyash is arbitrarily stacked, Soil Surrounding and environment can be polluted, if comprehensive Potential risk is also likely to be present using improper.Table 3-3 show flyash, CaO and flyash and each 2.00g mixtures of CaO, extremely The leaching content of each element after 24h is vibrated in 50mL water, raw materials of Ca O has Ba, Na, K, Mg, S impurity as seen from table, wherein Ba, Na, Mg content are less, and K, S content are higher.It is added to the water with 2g: 2g proportioning when by two kinds of raw materials, effectively prevents powder The dissolution of Al, As, B, Mo, Mg, Ni, S, Sb, Si, V, Cr in coal ash raw material, but the stripping quantity of Ba, K, Na is in increase compared with raw material Trend long, it is that this undissolved Ba, K, Na in flyash have been replaced in the addition of CaO that its reason is probably, and promotes Ba, K, Na Dissolution.

The total chromium stripping quantity (mg) of table 3-2 flyash

After table 3-3 vibrations 24h in raw material each element leaching content

Note：N.A. represent and do not contain.

3.1.3 the influence of duration of oscillation

As shown in Figure 4, under different adsorption times, in the range of 1~2h, the clearance of the total chromium of change over time is presented The trend of liter；In the range of 3~24h, the clearance of total chromium is on a declining curve.With reference to the interpretation of result of 3.1.2, because of flyash in itself Treatment effect to total chromium is not good, a small amount of chromium dissolution of the chromium in flyash in oscillatory process, just can influence flyash Removal to total chromium in percolate.

3.1.4 the influence of solid-to-liquid ratio

With reference to the result of 3.3.2, the 24h chromium slag percolate result of the tests after the flyash treatment of different throwing amounts are carried out into sky It is white to deduct correction, different solid than influence of the flyash to total chromium removal effect as shown in figure 5, when flyash dosage exists During 0.5~7g, as the removal Changing Pattern of the total chromium of increase of flyash dosage is not obvious, but removal effect is with flyash Increase it is integrally in rising trend, every gram of utilization rate of flyash (mg/g) is on a declining curve, so the dosage of flyash is simultaneously It is not The more the better, while total adsorbance of flyash is ensured, premised on improving utilization of fly ash rates, selection 2.00g flyash is best feed rate.

The research of the total chromium efficiency of 3.2 Fly ash-CaO combined removals and mechanism

3.2.1 influence of the duration of oscillation to the total chromium effect of Fly ash-CaO combined removal

It will be appreciated from fig. 6 that with the increase of duration of oscillation, the clearance of total chromium is in rising trend, in 0~3h, clearance shows Writing increases, and 3~24h changes are slow, and 24h clearances tend to balance, and clearance can reach more than 94%.

3.2.2 influence of the concentration of total chromium to the total chromium effect of Fly ash-CaO combined removal

As shown in Figure 7, in low strength range, matched curve relatively meets Langmuir adsorption isotherms, i.e. initial concentration Between 0.157~52.3mg/L, equilibrium adsorption capacity is directly proportional to initial concentration, and the continuation with initial concentration increases, activity The reduction in site, treating capacity gradually tends to saturation.When initial concentration is in below 0.80mg/L, total Chromium in Waste after treatment Content ＜ 0.05mg/L；When initial concentration is in below 8.5mg/L, the content ＜ 0.5mg/L of the total Chromium in Waste after treatment, when Total chromium initial concentration ＜ 80mg/L, total chromium clearance is up to more than 90%.So, when pending chromium slag total Chromium in Waste content mistake Gao Shi, it is ensured that water outlet reaches discharge standard after treatment, should take water-reducible method to anticipate waste water.

3.2.3 the dosage of CaO removes the research of total chromium efficiency to flyash

As shown in Figure 8, with the increase of CaO throwing amounts, the total chromium of Fly ash-CaO combined removal is reached used by removal balance Time is shorter, but extension over time, and the CaO of different throwing amounts is fewer to the clearance difference of total chromium, and clearance is equal within 24 hours Reach more than 88%.It can be seen that the addition of CaO can significantly improve removal effect of the flyash to total chromium, small amount is used CaO substitute flyash, and increase duration of oscillation, it becomes possible to reach preferable removal effect, and if the shorter vibration of selection Time, the effect for preferably removing total chromium is reached, then need to increase the input amount of CaO, but now under the utilization rate general of CaO Drop.

Row element complete analysis is entered to the chromium slag percolate after treatment, 3-4 is the results are shown in Table, this is understood by contrast after before processing Chromium pulp water toxicity after method treatment weakens.The stripping quantity of Ba, K, Na, Mo shows a rising trend compared with raw material, and wherein Mo is chromium Non-existent element in slag percolate, thus the Mo sources after explanation treatment in solution are flyash, and Ba, K, Na content are improved, Reason is that this undissolved Ba, K, Na in flyash have been replaced in the addition of CaO, promotes the dissolution of Ba, K, Na, and other elements contain Amount is on a declining curve, illustrates that the addition of CaO is preferable to other element treatment effects in flyash treatment chromium slag percolate.

Treatment effect after table 3-4 Fly ash-CaOs treatment chromium slag percolate 24h

Note：Content increases after ↑ expression treatment, and content is reduced after ↓ expression treatment, without significant change after-expression before processing.

3.2.4 total chromium leaching test of residue after processing

As shown in table 3-5, for a kind of independent inorganic agent, with the increase of solid-to-liquid ratio, treating capacity is integrally in rising Trend.Three kinds of inorganic agents of identical solid-to-liquid ratio are compared, and Fly ash-CaO combines maximum to the treating capacity of total chromium.Leaching test data Show, three kinds of inorganic agents of identical solid-to-liquid ratio, the total chromium leaching rate of the residue containing chromium with flyash as inorganic agent is maximum, with fine coal Ash-CaO is minimum for the total chromium leaching rate of residue containing chromium of inorganic agent, and in residue far smaller than after other two kinds of inorganic agents treatment The leaching rate of total chromium, illustrates that Fly ash-CaO synergy can limit total chromium leaching in residue, and this restriction effect is with CaO The increase of throwing amount and effect is more obvious.

Table 3-5 leaching test results

Check experiments of 3.3 CaO to total chromium removal effect

3.3.1 the influence of duration of oscillation

Fig. 9 shown in the case of different duration of oscillations, and CaO changes over time curve to total chromium clearance, and with it is identical The Fly ash-CaO mixture (2.00g+2.00g) of solid-to-liquid ratio compares, and when duration of oscillation is less than 2h, CaO acts solely on total chromium Removal effect be better than Fly ash-CaO mixture, be probably chromium the reason for produce this phenomenon with the increase of duration of oscillation The generation of sour calcium precipitate or Ca (OH)₂Suction-operated so that total chromium clearance rises rapidly in a short time；Work as duration of oscillation More than 2h, coal ash-CaO mixtures are independent as place as the extension of duration of oscillation is significantly larger than CaO to the removal effect of total chromium The effect of agent is managed, removals of the CaO to total chromium is on a declining curve, its reason is probably that the part chromate to be formed is precipitated or in absorption The chromate of state dissolves again under conditions of vibration, is illustrated by contrast test, the chromium slag diafiltration after being processed during through 24h Liquid, 2.00g flyash substitution 2.00g CaO, improves the clearance of total chromium.

3.3.2 the influence of CaO dosages and the initial concentration of total chromium

The initial concentration of total chromium is 49.11mg/L and 22.78mg/L, and the check experiment of different liquor ratios is shown in Figure 10-11, by scheming 10 understand, when total chromium initial concentration be 49.11mg/L, CaO dosages in the range of 2.5~7g, with the increasing of CaO input amounts Plus, the clearance of total chromium increases, and the amount that average every gram of CaO processes total chromium drops to 0.25mg/g, the utilization of CaO from 0.61mg/g Rate reduction, in the case of identical solid-to-liquid ratio, when individually delivering CaO alignment processing amount be compared with Fly ash-CaO Combined Treatment, Clearance is significantly lower than the latter.As shown in Figure 11, when total chromium initial concentration is 22.78mg/L, and CaO input amounts are 2.5~4g, Average every gram of CaO treating capacity is about 0.22mg/g, when input amount is more than 5g, continues to increase CaO dosages, average every gram of CaO Treating capacity to total chromium is divided into 0.18mg/g, 0.15mg/g, 0.13mg/g, and alignment processing amount is and fine coal when individually delivering CaO Ash, CaO Combined Treatments are compared, and clearance has significantly lower than the latter.In view of removals of the above result of the test deducibility CaO to total chromium Amount is relevant with the initial concentration of total chromium, in total chromium initial concentration in the range of 22.78~49.11mg/L, with initial concentration Raise, CaO removes the efficiency amount of increasing of total chromium, this process is relevant with the precipitation reaction of chromate with Ca.By 3-6 pairs, table Understood than result, the flyash of part mass replaced with CaO, i.e., both participate in the removal process of total chromium jointly, and with it is independent Compared using the result of CaO, flyash, as a result shown in different solid ratio, flyash individually processes total chromium, and action effect is most Weak, the treatment effect of the total chromium of Fly ash-CaO combined removal is all higher than individually using CaO or flyash.

With the increase of CaO input amounts, in the case of two kinds of various concentrations, role is different.It is low in 22.78mg/L During concentration, more rare group of I of the input amount (2, No. 3) of CaO, synergy effect is more obvious, CaO treating capacities is relatively used alone and improves 87.4%；In 49.11mg/L high concentrations, it is 2: 2 to be matched at both, and when seeing a group III (8, No. 9), synergy effect is more Plus substantially, now the utilization rate highest of CaO, relatively solely improves 33% using CaO treating capacities.

Total chromium initial concentration is 22.78mg/L, the result shown in a group I (No. 1), place of the 2.00g flyash to total chromium Reason amount ＜ 0.089mg, result understands shown in group II (No. 5), and 3.00g CaO are 0.650mg to the treating capacity of total chromium, and both always locate Reason amount sum ＜ (0.089+0.65) mg, in Fly ash-CaO is mixed to join the diafiltration of chromium slag with (2.00g+3.00g), is shown in group Result shown in IV (No. 12), treating capacity is 1.098mg, it can thus be appreciated that Fly ash-CaO combines the removal to total chromium, and not both The simple for the treatment of effect adds and also not simple suction-operated of the solid phase to liquid phase during exclusive use.

The total chromium removal effect tables of comparisons of table 3-6

3.3.3 the influence of the dosing method of CaO

Figure 12 shows the removal effect of the wet mixing agent to total chromium of the CaO aquation modified coal ash of different ratio under different time Really, as seen from the figure, with the extension of duration of oscillation, wet mixing agent A~F is in be gradually increasing trend, 24h to the removal effect of total chromium Tend to balance.In the case of showing different duration of oscillations in Figure 13~19, dry-mixed dose of identical solid-to-liquid ratio with wet mixing agent to total chromium Removal effect comparison diagram, contrasted under the conditions of random time, no matter wet mixing agent or dry-mixed dose, CaO dosages are more, reach Time to balance is shorter, and the treatment effect to total chromium is better.When duration of oscillation is 24h, the increase of the throwing amount of CaO, For the dry-mixed dose of total chromium of removal without significant difference but larger on the total chromium influence of wet mixing agent removal, this influence is thrown with CaO The increase of amount is gradually decreased.Figure 13~16 comparing result shows, vibrating in initial 3h, dry-mixed dose of any solid throwing amount to total The treatment effect of chromium is better than wet mixing agent, and Figure 17~18 comparing result shows, when solid throwing amount is less than 4.00g, i.e., (flyash+ CaO)≤4.00g, the dry-mixed dose for the treatment of effect to total chromium is better than wet mixing agent.Figure 19 comparing results show, any solid throwing amount The dry-mixed dose for the treatment of effect to total chromium is better than wet mixing agent.Analysis based on the above results understands that Fly ash-CaO is with directly mixing Mode is put into chromium slag percolate, when solid throwing amount is 3.00g (flyash 2.00g+CaO 1.00g), 4.00g (flyash 2.00g+CaO 2.00g) when, at any duration of oscillation, the removal effect to total chromium is superior to previously prepared wet mixing agent.By This understands that dry-mixed dose relevant with the time to the removal effect of total chromium with wet mixing agent, and possible cause is removal of the wet mixing agent to total chromium Based on absorption, and dry-mixed dose of CaO can directly react in aqueous with flyash, and chromium can participate, initial rank Section reaction speed is very fast (in 3h), and total chromium relatively rapidly enters solid phase, now shows as the treatment effect better than wet mixing agent, with The extension (5h, 7h) of time, the reaction speed in dry-mixed solution slows down gradually, and high content CaO wet mixing agent treatment effects occurs excellent In dry-mixed dose of phenomenon of identical solid-to-liquid ratio.In sum, dry-mixed dose is selected as inorganic agent, and the dosage of CaO should not be excessive, Flyash is 2: 2, or 2: 1 more suitable with the proportioning of CaO.

The research of the total chromium curing mechanism of 3.4 Fly ash-CaO combined removals

3.4.1 SEM surface textures are characterized

3.4.1.1 the structural characterization of flyash

The microscopic appearance of flyash determines its macroscopic view reason, changes property, and knowable to Figure 20-21, electric precipitation flyash has Spheroidal and amorphous two kinds, bead is more complete, and surface is smoother, mostly in the single spheroid or multiple of the rule that differs in size The connected multiple pearl of monomer, surface pores is less, there is a small amount of spherical flyash in hollow state in addition, is grafted on hole wall without fixed Type thing or glass microballoon, amorphous substance may be free oxide, also a small amount of unformed vitreum.From the surface of flyash Structure understands that its adsorption capacity to total chromium of the structures shape of the smooth less porous of flyash is limited.Complete sphere surface microcell is entered Row EDX energy spectrum analysis, is shown in Figure 22, and each element content is shown in Table 3-7, and as seen from table, microsphere surface is based on O, Si, Al, Fe, Ca.

The table 3-7 EDX composition tables of comparisons

Element	Wt%	At%
			CK	06.02	12.11
OK	16.93	25.58
			NaK	03.14	03.30
MgK	00.19	00.19
			AlK	18.53	16.61
SiK	40.03	34.47
			KK	01.70	01.05
CaK	04.60	02.78
			TiK	01.00	00.50
FeK	07.87	03.41
			Matrix	Correction	ZAF

3.4.1.2 the modified flyash SEM of CaO aquations is characterized

Powder to Fly ash-CaO (2.00g: 2.00g) carries out hydration process, and from SEM Figure 23-24, sample occurs There is sheet and acicular crystal in agglomeration, microsphere surface, and wherein laminated structure is Ca (OH)₂。

Based on glass phase, main component is SiO to flyash₂And Al₂O₃, flyash+CaO is added in water, after reaction：

mCa(OH)₂+nSiO₂+yH₂O=(CaO) m (SiO₂)n(H₂O)y+m

mCa(OH)₂+xAl₂O₃+yH₂O=(CaO) m (Al₂O₃)x(H₂O)y+m

mCa(OH)₂+xAl₂O₃+nSiO₂+yH₂O=(CaO) m (SiO₂)n(Al₂O₃)x(H2O)y+m

From above-mentioned reaction, acicular texture is the product after aquation.EDX energy spectrum analysis is carried out to microcell, figure is as a result seen 25, table 3-8.

The modified flyash EDX composition tables of comparisons of table 3-8 CaO aquations

Element	Wt%	At%
			CK	18.97	32.47
OK	19.24	24.73
			NaK	03.25	02.90
MgK	00.00	00.00
			AlK	12.06	09.19
SiK	34.33	25.13
			KK	01.29	00.68
CaK	05.67	02.91
			TiK	01.15	00.49
FeK	04.04	01.49
			Matrix	Correction	ZAF

3.4.1.3 the SEM containing chromium residue is characterized

By Fly ash-CaO with 2.00g: 2.00g proportioning input Cr solution systems in, as a result see Figure 26-27, with 3.4.1.2 Comparative result understands that in the case of the participation for having chromium, fly ash microsphere structure is not affected by destruction, on its surface and Around reunite, form tufted crystal, a portion crystal in the form of sheets, another part carries out EDX in needle-like to its microcell Energy spectrum analysis, is as a result shown in Figure 28 and table 3-9, is analysed by Elemental Composition, and laminated structure calcium hydroxide, acicular texture may be containing chromium Crystal, its mechanism of action may be the SiO that dissociates in flyash₂、Al₂O₃With CaO during hydration reaction by CrO₄ ^2-With layer Between the form of anion be fixed in crystal structure, there is the part flyash during fine coal gray surface, reaction in reaction Grain is covered by newly-generated material.

The table 3-9 EDX composition tables of comparisons of residue containing chromium

Element	Wt%	At%
			CK	21.85	35.71
OK	27.40	33.62
			NaK	02.33	01.99
MgK	00.82	00.66
			AlK	10.27	07.47
SiK	14.94	10.44
			CaK	15.79	07.73
CrK	01.88	00.71
			FeK	04.71	01.66
Matrix	Correction	ZAF

3.4.2 XRD Crystal Structures

3.4.2.1 former flyash and aquation modified coal ash XRD crystal structure analyses

As shown in Figure 29, former flyash crystal structure is with SiO₂Based on, compared with raw material flyash, the crystalline substance of modified coal ash Body structure there occurs change, within the specific limits, with the increase of CaO mass, Ca (OH) occurs₂Crystal structure, and peak intensity is gradually By force, this is relevant with CaO additions, SiO₂Peak intensity weakens, when flyash: calcium oxide=2: when 2, Ca (OH) occur₂、SiO₂Peak intensity It is most weak, when continuing to increase CaO mass, main Ca (OH) in sample₂Crystal, Ca (OH)₂、SiO₂The most weak generation of peak intensity is in fine coal Ash and calcium oxide proportioning 2: 2, Ca (OH) the reason for produce this phenomenon₂With SiO₂Interact, mutually wrap up, during 2: 2 proportioning The SiO of fine coal gray surface₂、Al₂O₃It is suitable with CaO amounts of reactants numbers, now CaO utilization rates highest, this and upper 3.3.2 results phase Unanimously.

3.4.2.2 the XRD crystal analyses containing chromium residue

XRD crystal analyses are carried out to residue containing chromium, and is contrasted with CaO aquations modified coal ash (2: 2), can by Figure 30 Know, relative to the CaO aquation modified coal ash for not thering is chromium to participate in, SiO in residue containing chromium₂Content reduces diffraction at 2 θ=26.66 Peak intensity weakens.Occurs fainter new diffraction maximum at 2 θ=23.14, this peak may be chromate, because of chromium content phase in residue To less, part diffraction maximum overlaps with the structure peak in residue in chromate crystal, therefore more difficult sign chromate.

3.4.3 infrared functional group characterizes

The infrared spectrum of powdered coal ash is shown in Figure 31 (a), wherein 1100cm^-1Place's broad peak is with SiO₂Based on oxide stretch The conjunction peak of contracting vibration peak, including the anti-stretching vibrations of Si-O-Si, Al₂O₃Stretching vibration peak, P=O stretching vibration peaks, SO₃ Symmetrical stretching vibration etc..800cm^-1、771cm^-1Place is in crystalline state SiO₂Symmetrical stretching vibration peak, 470cm^-1Place include be with SiO₂、Fe₂O₃、TiO₂Deng flexible and flexural vibrations.Known CaO is in 4000~400cm^-1In the range of without absworption peak, by flyash It is well mixed in varing proportions with CaO, obtained inorganic agent infrared spectrum is shown in Figure 31 (b~g) after adding water, with the increasing of CaO Plus 1490,1418cm^-1Place's absworption peak gradually strengthens, and this is the antisymmetric stretching vibration absworption peak of carbonate, the strong double suction in wide Receive peak, 878cm^-1There is the sharper out-of-plane bending vibration absworption peak of carbonate in place, during above analytic explanation aquation Generate more CO₃ ^2-, 3645cm^-1Place occur in that point and strong hydroxide absworption peak, this hydroxide absworption peak is with Ca (OH)₂Based on.In addition, in 1300~400cm^-1In the range of fingerprint region, with the addition of CaO, compared with former flyash, this area essence Fine texture changes, and belongs to 1100cm in powdered coal ash^-1、1018cm^-1、470cm^-1Place absorbs peak-to-peak relative intensity hair Changing, thus illustrates that the addition of CaO have impact on the change of each component content in former flyash, for the ease of semi-quantitative analysis, With 1100cm^-1Peak on the basis of place's absworption peak, with other at two absorption peak strength do ratio, the results are shown in Table 3-10, as seen from table, with The increase of CaO incorporations, 1018cm^-1、470cm^-1The absworption peak at place is in the trend for reducing, when flyash is with CaO proportionings When 2: 2,1018cm in powdered coal ash^-1、470cm^-1Place's absworption peak has significant change, when flyash and CaO ratios increase to 2: 4,470cm^-1The absworption peak at place almost disappears, and illustrates that this hydration process destroys the structure of oxide in flyash.

Table 3-10 fine structures change the table of comparisons

Residue containing chromium after processing as shown in Figure 32,470cm^-1The absworption peak at place almost disappears, and its possible cause is, aquation During dissolved some free metal oxides in powdered coal ash, such as Fe₂O₃, but treatment after solution in Fe unit Cellulose content is less, therefore Fe should be attached to fine coal gray surface in the form of colloid, and EDX analyses are carried out to microcell, see 3.4.1.3, show that Fe take part in the formation of crystal structure.

The research of 3.5 technology restriction factors

3.5.1 the purifying of humic acid

3.5.1.1 the Fluorescent Characterization of humic acid

Contain plurality of impurities composition in known available humic acid, for the ease of carrying out quantitative analysis to humic acid, it is necessary to right Humic acid carries out more purification treatment.Fluorescence spectrum scanning, three-dimensional spectral scan are carried out to each step solution 1,3,4 in purge process Result is shown in Figure 33-35, and Figure 33 show the fluorescent material in humic acid water lotion, maximum excitation wavelength Ex：270nm emission maximums Wavelength Em：436nm 467nm, it may be possible to a small amount of fulvic acid composition being mixed with former humic acid, Ex：220nm or so exists a small amount of Protein component；Fluorescent material in No. 3 solution, i.e. pickle shown in Figure 34, maximum excitation wavelength Ex：290nm, maximum hair Ejected wave Em long：449nm 469nm, the protein ingredient in pickle disappears with fulvic acid composition；Humic acid 4 after purified is molten Liquid is as shown in figure 35, maximum excitation wavelength Ex：280nm, maximum emission wavelength Em：447nm 469nm, compared with Figure 34, excite Wavelength there occurs red shift, but transmitting position is almost unchanged, and possible cause is the washing of acid solution so that ash content composition is reduced, Acid soluble impurities composition is disappeared, and the fluorescence interfering material of humic acid is reduced so that excitation wavelength produces red shift.Result shows：No The component in solution difference formed with purification step, illustrate that each step is washed and plays certain effect to the purifying of humic acid.

3.5.1.2 the IR Characterization of humic acid

The basic structure of known humic acid macromolecular is aromatic ring and alicyclic ring, and carboxyl, hydroxyl, carbonyl, quinonyl, first are connected with ring The functional groups such as epoxide.Former commercially available humic acid A, the humic acid B after being washed, the humic acid C after pickling processes are carried out respectively Infrared spectrum measurement, as a result as shown in figure 36,3 300~3 500cm^-1Place occurs in that the-O-H stretching vibration broad peaks of association, 1710cm^-1There are carbonyls-C=O stretching vibration spikes at left and right, in 1600cm^-1The C-C that aromatic hydrocarbons occurs in place stretches, hydrogen bond With reference to quinonyl and carboxylic acid ion, in 900~1000cm^-1Between show skeletal vibration and the stretching vibration of-C-C.Washing Without obvious difference between rear humic acid B and former humic acid A, the humic acid C after pickling processes compared between former humic acid, 1710cm^-1Left and right carbonyl peak becomes obvious, 3 300~3 500cm^-1- O-H the stretching vibration peaks for associating are obvious, it may be possible at acid HA after reason, destroys the complexing degree between HA and metal ion, and the carboxyl complexing of metal ion of humic acid, complex disintegrate, Intramolecular carboxyl complexing is strengthened.

3.5.2 researchs of the pH on the ultravioletvisible absorption characteristic influence of humic acid and chromium

3.5.2.1 influences of the pH to humic acid ultravioletvisible absorption characteristic

12.5mg/L humic acids are carried out into uv-vis spectra scanning under acid and neutrallty condition respectively, such as Figure 37 institutes Show, as a result show, humic acid has different degrees of absorption in whole UV-visible region, there is no characteristic absorption peak, and in acidity Under the conditions of, humic acid can be reduced in whole ultraviolet and visible absorption peak intensity, it follows that acid condition is compared with destructible humic acid Conjugated structure.

3.5.2.2 influences of the pH to Cr (VI) ultravioletvisible absorption characteristics and form

It is 0.5, Cr (VI) ion distribution feelings in the case of 0.05 to obtain ionic strength using the fitting of Visual MINTEQ softwares Condition pH is as shown in figure 38.It is 40mg/L K to the concentration of pH 1.0~12.0₂CrO₄The ultraviolet-visible absorption spectroscopy of solution, is shown in Figure 39, Result shows, K₂CrO₄There are two characteristic absorption peaks in ultra-violet (UV) band, in the scopes of pH ＜ 4, CrO₄ ^2-Absorption maximum peak position and rub Your absorptivity is constant, and Cr (VI) is main with HCrO in solution₄ ^-Form is present, and the 99% of ion concentration is accounted for, as 4 ＜ pH ＜ 9 In the range of, with the increase of pH, its absorption maximum peak position gradually red shift, molar absorption coefficient gradually increases, 4~9, mainly with HCrO₄ ^-To CrO₄ ^2-The process for gradually changing, as pH ＞ 9, the position of maximum absorption wavelength is basic and molar absorption coefficient hardly Cr (VI) is main with CrO in becoming solution₄ ^2-Form is present, and this is almost consistent with Visual MINTEQ software fitting results.

3.5.2.3 influences of the pH to humic acid fluorescence intensity

In the scopes of pH 1~12, the humic acid to same concentrations carries out fluorescent absorbance determining, as a result sees Figure 40, can by figure Know, the fluorescence intensity of humic acid is relevant with pH, in the range of pH 1~7, with the increase of pH, fluorescence intensity enhancing, it may be possible to The Different Effects of the pH configuration of humic acid, in the range of pH 7~12, the fluorescence intensity of humic acid is gradually reduced, it may be possible to which corruption is planted The quinonyl of acid causes the change of fluorescence intensity with the change of phenolic hydroxyl structure.Therefore, with humic acid as inspection target, using molecule Fluorescence spectrum, indirect determination chromium is with humic acid reduction efficiency, it is necessary to investigate reduction of the humic acid to chromium in the case of being fixed on pH Effect, to exclude interference of the pH to humic acid fluorescence intensity.

3.5.2.3 pH reduces the research of Cr (VI) influences on humic acid

Figure 41 is shown under condition of different pH, the Cr (VI) of different quality is added, in Ex：275nm, Em：Measured at 475nm The fluorescence intensity of humic acid, humic acid oxygenation efficiency is calculated by the reduction situation of humic acid fluorescence intensity, is shown in Table 3-11, can by table Know, add different content Cr (VI), oxidability during pH 3.0 to HA is most strong, it is known that chromium has strong in acid condition Oxygenation efficiency is not high between oxidability, but pH 1.0~2.0, under possible cause is strong acidic condition, there is part humic acid Separate out.Therefore Cr (VI) is selected in pH 3.0 with humic acid optimum oxidation reducing condition.

Oxygenation efficiency (units of the Cr (VI) to HA under table 3-11 condition of different pH：%)

The standard curve of humic acid is as shown in figure 42,0.625~12.5mg/L of the range of linearity, therefore, as HA concentration ＞ During 12.5mg/L, the method for dilution should be taken to carry out Concentration Testing.HA with 12.5m/L as substrate, the Cr of various concentrations (VI) with HA quantitative reactions relation as shown in figure 43, Cr (VI) is added in low-level scope, the oxidation of HA as can be seen from Fig. Rate is directly proportional to Cr (VI) concentration, Cr (VI) and HA quantitative reactions, and Cr (VI) is in complete reducing condition, when continuing to increase Cr (VI) concentration, the clearance of HA increases in logarithm, and possible cause is that, when Cr (VI) content is high, HA increases with Cr (VI) complexing By force, oxidations of the Cr (VI) to HA is have impact on, when theoretical calculation proper Cr (VI) concentration reaches 59mg/L, HA is removed up to 100%.

3.5.4 research of the humic acid to the total chromium of Fly ash-CaO combined removal

As shown in figure 44, when adding HA in chromium slag percolate, compared with the chromium slag percolate without HA, under clearance is obvious Drop, this phenomenon converts Cr (III) with Cr (VI) under reducing condition, Cr (III) generations precipitation, Cr (VI) clearance under alkalescence condition The notional result of decline conversely, may HA combined with Fly ash-CaO, HA can be adsorbed on Fly ash-CaO surface, occupy surface Active reaction position, hinder the reaction of total chromium and Fly ash-CaO.Supernatant three-dimensional fluorescence spectrum as shown in Figure 45-46, Result show treatment after solution in without humic-acid-type substances, illustrate that the humic acid in solution has been transferred completely into solid phase.

4th, conclusion

Research of 4.1 flyash to the adsorption of total chromium

4.1.1 chromium slag material composition is complex, and Cr, Ca, Na, Mg, S etc. are easier to dissolution, former chromium during leaching Although containing Fe higher in slag, leaching rate is relatively fewer, element Cu, Zn, Ni, Co, Mn, Ti, V in chromium slag raw material etc. into Dividing does not have dissolution.

4.1.2 shown by flyash shaking test result：During vibration, total chromium in powdered coal ash and its Its element can the dissolution during vibration, for total chromium, with the increase of duration of oscillation, stripping quantity increases, and in 24h Tend to balance, amount of precipitation is 0.006mg/g.The time point of the maximum stripping quantity of other elements because of element nature and species not It is different together.The addition of calcium oxide can effectively prevent the dissolution of harmful element in flyash, but promote Ba, K, Na in flyash Dissolution.

4.1.3 flyash changes over time downward trend after presentation first rises to the removal efficiency of chromium slag percolate, goes out The reason for existing this phenomenon is probably that starting stage flyash has certain adsorption effect to total chromium in percolate, but adsorption rate has Limit, the leaching of extension powdered coal ash over time chromium in itself makes in solution that always chromium concn has been raised, when stripping quantity is more than During adsorbance, adsorption equilibrium of the flyash to total chromium is destroyed, so as to have impact on removal effect of the flyash to total chromium in percolate Really.

4.1.4 with the increase of flyash fixed liquor ratio, every gram of utilization rate of flyash (mg/g) is on a declining curve, is ensureing While total adsorbance of flyash, premised on improving utilization of fly ash rates, from the solid waste amount and cost consideration that produce, selection 2.00g flyash is best feed rate.

The research of the total chromium efficiency of 4.2 Fly ash-CaO combined removals

4.2.1 with the increase of duration of oscillation, Fly ash-CaO combines in rising trend to the clearance of total chromium, in 24h When tend to balance, clearance can reach more than 94%.

4.2.2 in low strength range, equilibrium concentration is directly proportional chromium to equilibrium adsorption capacity, and the continuation with initial concentration increases Plus, the reduction of avtive spot, removal amount gradually tends to saturation.

4.2.3 the addition of CaO can significantly improve removal effect of the flyash to total chromium, with the increase of CaO throwing amounts, powder The time that the total chromium of coal ash-CaO combined removals is reached used by removal balance is shorter, but extension over time, the CaO of different throwing amounts Clearance difference to total chromium is fewer, and clearance reaches more than 88% within 24 hours.Flyash is substituted with less amount of CaO, and Increase duration of oscillation, preferable removal effect can be reached, and if the shorter duration of oscillation of selection, to reach and preferably remove The effect of total chromium, then need to increase the input amount of CaO, but now the utilization rate of CaO will decline.After being processed through Fly ash-CaO Chromium pulp water toxicity weakens, but the method promotes the dissolution of Mo, Ba, K, Na in flyash.

4.2.4 total chromium is leached in residual residue after Fly ash-CaO synergy can be limited and processed, this restriction effect With the increase of CaO throwing amounts, effect is more obvious.

The check experiment that 4.3 independent CaO are removed to total chromium

4.3.1 when duration of oscillation is less than 2h, the removal effect that CaO acts solely on total chromium is better than Fly ash-CaO mixing Thing, when duration of oscillation is more than 2h, Fly ash-CaO mixture is to the removal effect of total chromium as the extension of duration of oscillation is long-range In CaO individually as the effect of inorganic agent.

4.3.2 Fly ash-CaO is combined to the non-simple absorption of removal effect of chromium slag percolate or precipitation, to total The removal effect of chromium depends on the dosage of CaO, but the utilization rate in Combined Treatment of CaO depends on the initial dense of total chromium Degree, as total chromium initial concentration 22.78mg/L, when the dosage of CaO is 0.50g, the utilization rate highest of CaO is relatively used alone CaO treating capacities improve 87.4%, when total chromium initial concentration is 49.11mg/L, when the dosage of CaO is 2.00g, CaO's Utilization rate highest, relatively solely improves 33% using CaO treating capacities.

4.3.3 the solid (wet mixing agent) after Fly ash-CaO directly being mixed into (dry-mixed dose) and Fly ash-CaO hydration reaction Contrasted, examined or check both treatment effects to total chromium in chromium slag percolate, result of study is shown, the quality of both treatment effects Dosage with duration of oscillation and CaO is relevant.Contrasted under the conditions of random time, no matter wet mixing agent or dry-mixed dose, CaO throws Dosage is more, and the time for reaching balance is shorter, and the treatment effect to total chromium is better.When duration of oscillation is 24h, CaO's The increase of throwing amount, for the dry-mixed dose of total chromium of removal without significant difference but larger on the total chromium influence of wet mixing agent removal, this influence is made Gradually decreased with the increase with CaO throwing amounts.Vibrating in initial 3h, the dry-mixed dose for the treatment of effect to total chromium of any solid throwing amount Fruit is better than wet mixing agent, and when duration of oscillation is 5h, 7h, when solid throwing amount is less than 4.00g, i.e. (flyash+CaO)≤4.00g does Mixture is better than wet mixing agent to the treatment effect of total chromium.When duration of oscillation is 24h, dry-mixed dose of any solid throwing amount to total chromium Treatment effect is superior to wet mixing agent.In sum, dry-mixed dose is selected as inorganic agent, and the dosage of CaO should not be excessive, fine coal Ash is 2: 2, or 2: 1 more suitable with the proportioning of CaO.

4.4 Fly ash-CaOs joint is except the research of total chromium mechanism

Total chromium mechanism is removed to Fly ash-CaO joint with reference to SEM surface textures, XRD crystal structures, infrared structure of functional groups Be analyzed, as a result show, on fly ash microsphere surface, the presence of chromium has promoted the shape of tufted crystal structure to Crystallization Into a small number of free CaO, Al in flyash structure₂O₃、SiO₂、Fe₂O₃Take part in Crystallization.

The research of 4.5 humic acids and Cr (VI) interaction relationship

4.3.1 a small amount of ash content and fulvic acid in commercially available humic acid can be removed using the method for pickling, washing.

4.3.2 in acid condition, humic acid can be reduced in whole ultraviolet and visible absorption peak intensity, it follows that acid Conjugated structure of the condition compared with destructible humic acid.K₂CrO₄There are two characteristic absorption peaks in ultra-violet (UV) band, it is molten in the range of pH ＜ 4 Cr (VI) is main with HCrO in liquid₄- form is present, in the range of 4 ＜ pH ＜ 9, mainly HCrO₄- to CrO₄ ^2-Gradually change Process, as pH ＞ 9, Cr (VI) is main with CrO in solution₄ ^2-Form is present.

4.3.3 the fluorescence intensity of humic acid is relevant with pH, if with humic acid as inspection target, using molecular fluorescence spectroscopy, Indirect determination chromium and the reduction efficiency of humic acid, need to exclude interference of the pH to humic acid fluorescence intensity.

4.3.4 in pH 3.0 humic acid and Cr (VI) redox efficiency highest.Because of Cr (VI) in acid condition With strong oxidability, but oxygenation efficiency is not high in 1.0~2.0 scopes of pH, it may be possible to because under strongly acidic conditions, having Part humic acid is separated out.

4.3.5 when Cr (VI) dosage is in low-level scope, the oxygenation efficiency of HA is directly proportional to Cr (VI) concentration, Cr (VI) with HA quantitative reactions, and Cr (VI) is in complete reducing condition, and when continuing to increase Cr (VI) concentration, the clearance of HA is in right Number increases, the reason for produce this phenomenon may for Cr (VI) content it is high when, HA strengthens with Cr (VI) complexing, have impact on Cr (VI) to the oxidation of HA.

4.3.6 the presence of HA, influence Fly ash-CaO to the treatment effect of chromium slag percolate, this and Cr under reducing condition (VI) conversion Cr (III), Cr (III) generations precipitation under alkalescence condition, the notional result that Cr (VI) clearance declines is opposite.Cause The reason for this phenomenon is probably that HA is combined with Fly ash-CaO, and is adsorbed on flyash, CaO surfaces, causes total chromium and fine coal The decline of the reaction rate of ash-CaO.

Claims (5)

1. a kind of chromium slag leachate contamination soil emergence treating method, it is characterised in that methods described step is as follows：

Step one, the initial concentration scope for determining total chromium in soil surface chromium slag percolate first, when pending chromium slag is percolated When total chrome content is too high in liquid, water-reducible method beforehand dilution should be taken to process the chromium slag percolate of soil surface, concentration control System is in the range of 0.157~52.3mg/L；

Step 2, by Fly ash-CaO dry-mixed dose be added in the chromium slag percolate of step one, control solid-to-liquid ratio be 2.5~7： 50, the two mass ratio is 2 in dry-mixed dose of flyash-calcium oxide:0.5~5；

Step 3, chromium slag percolate and flyash-calcium oxide are sufficiently mixed 7~24 with the mixing speed of 100~300r/min h。

2. chromium slag leachate contamination soil emergence treating method according to claim 1, it is characterised in that the flyash- The two mass ratio is 2 in dry-mixed dose of calcium oxide:1 or 2:2.

3. chromium slag leachate contamination soil emergence treating method according to claim 1, it is characterised in that the solid-to-liquid ratio It is 4：50.

4. chromium slag leachate contamination soil emergence treating method according to claim 1, it is characterised in that the stirring speed It is 150r/min to spend.

5. chromium slag leachate contamination soil emergence treating method according to claim 1, it is characterised in that during the mixing Between be 24 h.